ABSTRACT
The Russian wheat aphid, Diuraphis noxia (Mordvilko) (Homoptera: Aphididae), reproduces parthenogenetically in North America and must survive year-round on host plants, including in late summer when small grains are not in cultivation. During this time, cool-season perennial wheatgrasses (Poaceae: Triticeae) contribute substantially to aphid survival, crested wheatgrass (Agropyron spp.) particularly. In greenhouse studies, the number of aphids per plant was measured after four infestation periods on unvernalized and vernalized wheatgrasses. Before placement on these test plant species, aphids were reared either on winter wheat or on the grass host species on which aphid progeny were counted. On vernalized plants, aphids reared on wheat resulted in more aphids per test plant than when the aphids were reared on wheatgrasses, but on unvernalized plants the number of aphids per test plant did not differ significantly regardless of rearing host. Aphids on crested wheatgrass were similar in number to the other grasses when plants were unvernalized. However, when plants were vernalized, crested wheatgrass supported significantly more aphids than some of the other hosts. Aphid numbers increased on all test species as infestation period lengthened, and plant growth was largely unaffected by aphid feeding. These results suggest if sufficient moisture is available during summer when small grains are not in cultivation, all host species observed are capable of sustaining aphids. Crested wheatgrass is an abundant and important host of the Russian wheat aphid in its northern range of the western United States, but other less prevalent wheatgrasses also may contribute to aphid survival during late summer when small grains are not in cultivation.
Subject(s)
Aphids , Poaceae , AnimalsSubject(s)
Emetine/pharmacology , Liver/drug effects , Protein Biosynthesis , Amino Acids/metabolism , Animals , Carbon Isotopes , Female , Isomerism , Liver/metabolism , RatsSubject(s)
Aminopyrine/metabolism , Emetine/pharmacology , Mercaptopurine/metabolism , Microsomes, Liver/metabolism , Morphinans/metabolism , Nucleosides/metabolism , Aniline Compounds/metabolism , Animals , Azo Compounds/metabolism , Carbon Monoxide/pharmacology , Cytochromes/metabolism , Dealkylation , Female , In Vitro Techniques , Kinetics , Metabolism/drug effects , Microsomes, Liver/drug effects , Microsomes, Liver/enzymology , NADP , Nitrogen/pharmacology , Oxidoreductases/metabolism , Rats , Ribonucleosides/metabolism , Tetrazolium SaltsSubject(s)
Emetine/pharmacology , Microsomes, Liver/metabolism , Protein Biosynthesis , Animals , Carbon Radioisotopes , DNA/biosynthesis , Dactinomycin/pharmacology , Deoxycytidine Monophosphate , Ethionine/pharmacology , Female , Hepatectomy , Liver Regeneration , Nucleotide Deaminases/metabolism , Phenylalanine/metabolism , Rats , Thymidine/metabolism , Thymidine Kinase/metabolism , Time Factors , TritiumSubject(s)
Aminopyrine/metabolism , Liver/metabolism , Microsomes, Liver/metabolism , Protein Biosynthesis , Animals , Carbon Isotopes , Dealkylation , Death , Female , Liver/anatomy & histology , Liver/cytology , Microsomes, Liver/drug effects , Organ Size , Peptide Chain Initiation, Translational , Phenylalanine/metabolism , Polynucleotides/pharmacology , RNA, Messenger/pharmacology , Rats , Rats, Inbred Strains , Subcellular Fractions/drug effects , Subcellular Fractions/metabolism , Temperature , Time Factors , Uracil Nucleotides/pharmacologyABSTRACT
1. Pretreatment of female rats with (-)-emetine or (+/-)-2,3-dehydroemetine (at 18mumol/kg body wt. for 24h) prolongs the hexobarbital-induced sleeping-time of the treated animals. 2. This effect is not observed on pretreating animals with other compounds closely related to (-)-emetine, such as (-)-isoemetine or (+)-O-methylpsychotrine. 3. Liver microsomal drug-metabolizing enzyme activity in vitro as measured by N-demethylation of aminopyrine and azo-reduction of Neoprontosil is inhibited in rats pretreated with (-)-emetine or with (+/-)-2,3-dehydroemetine. 4. These inhibitory effects on drug metabolism in vitro are not observed in corresponding experiments involving pretreatment of rats with (-)-isoemetine or (+)-O-methylpsychotrine. 5. Co-administration of emetine or 2,3-dehydroemetine and sodium phenobarbital or 1,1-dichloro-2-o-chlorophenyl-2-p-chlorophenylethane to rats abolishes or greatly diminishes the stimulation of drug-metabolizing enzyme activity in vitro usually obtained by the administration of phenobarbital or 1,1-dichloro-2-o-chlorophenyl-2-p-chlorophenylethane alone. 6. Further, in rats pretreated with sodium phenobarbital and subsequently injected with emetine or 2,3-dehydroemetine the pre-stimulated drug-metabolizing enzyme activity in vitro is diminished. 7. The inhibitory effects on drug-metabolizing enzyme activity after pretreatment with (-)-emetine or (+/-)-2,3-dehydroemetine do not appear to be related to NADPH generation.
